The condition of a female vaginal cavity during a Sexual Transmitted Disease. Scabs form over the open sores in the cavity and produce a very rigid environment.
Men who venture into these tough tunnels often are met with much friction and a gritty, sandpaper-like feeling during intercourse. Often producing open woulds and sores on the head and shaft of the cock, but produce a kind of accomplishment on the part of the conquerer of this cheese-grater like trophy.

Ricky Milton was gonna get him his first hooker with his birthday money he got from his mom. When he finally got naked and inserted into his new birthday present he was greeted with a the GRIT SLIT from hell. Being the non-quitter he is, he was determined to ride Sandpaper Sally to the end. So he pumped and pumped until his bone exploded all over it. The next few weeks he spent pissing blood and peeling scabs.